In these data sets the index "I" refers to longitude,"J" to latitude, "K" to the vertical dimension, and "L" to time. In the listing the values undereach qualifier present the points available along that axis. For example1:180 indicates that locations 1 through 180 are represented in the data set.
FERRETallows the user to probe the data set by slicing along various planesand axes, interactively examining raw and transformed data.
In FERRET all variables are regarded as defined on grids. Thegrids tell FERRET how to locate the data in space and time (orwhatever the underlying units of the grid axes are). Information describing a region in space/time, a data set and a gridis collectively referred to as the "context".
The indices I, J, K, and L refer to positions on aline along one of the dimensions of a grid. The line is dividedinto n points, or more precisely, n grid boxes where each grid box isa length along the axis. A grid is a group of 1 to 4 axes defining a coordinate space.
The indices refer to grid locations in which thepoints along an axis are regarded as integers from 1 to the number ofpoints on the axis. The qualifiers I, J, K and L are provided tospecify locations by subscript.